[testlib] move repo and related attribute back on Instance instead of Class
The repo and cnx was hold by the TestCase class to work as a cache and avoid
recreation of the repo from scratch of each test. However since bad26a22fe29 the
caching is done by the DatabaseHandler object and it is not necessary have a
second layer of cache on the TestCase itself.
We move the repo and cnx attribute back on the TestCase instance itself and make
several class methods instance methods again.
This will helps to change dbapi access in test from dbapi to repoapi.
related to #2503918
include README
include COPYING
include COPYING.LESSER
include pylintrc
include bin/cubicweb-*
include man/cubicweb-ctl.1
recursive-include doc README makefile *.conf *.js *.css *.py *.rst *.txt *.html *.png *.svg *.zargo *.dia
recursive-include misc *.py *.png *.display
include web/views/*.pt
recursive-include web/data external_resources *.js *.css *.py *.png *.gif *.ico *.ttf
recursive-include web/wdoc *.rst *.png *.xml ChangeLog*
recursive-include devtools/data *.js *.css *.sh
recursive-include i18n *.pot *.po
recursive-include schemas *.py *.sql
recursive-include test/data bootstrap_cubes *.py *.sql
recursive-include entities/test/data bootstrap_cubes *.py
recursive-include sobjects/test/data bootstrap_cubes *.py
recursive-include hooks/test/data bootstrap_cubes *.py
recursive-include server/test/data bootstrap_cubes *.py source* *.conf.in *.ldif
recursive-include devtools/test/data bootstrap_cubes *.py *.txt *.js
recursive-include web/test/data bootstrap_cubes pouet.css *.py
recursive-include web/test/jstests *.js *.html *.css *.json
recursive-include web/test/windmill *.py
recursive-include skeleton *.py *.css *.js *.po compat *.in *.tmpl
prune doc/book/en/.static
prune doc/book/fr/.static
prune doc/html/_sources/
prune misc/cwfs
prune goa